ADN by Tim Bradner (NGP File Photo).  One project is the big 1,700-mile, 48-inch pipeline from the North Tim Bradner by Dave Harbour, Gas Pipeline, AGDC, AGPA, ANGDA, AGIASlope to Alberta, which is in an engineering phase. TransCanada Corp. and Exxon Mobil Corp. are involved, both large, competent companies that know what they’re doing. However, with all the shale gas in the Lower 48, this project doesn’t look very good for now. But who knows what things will look like in 20 to 30 years?  If this is built, a smaller "spur" pipeline could branch off at Delta to bring gas 300 miles to Southcentral Alaska via Glennallen. The Alaska Natural Gas Development Corp., or ANGDA, a state authority, has done work on this.  If the big pipeline doesn’t go, engineering is under way on a fallback plan, a separate, stand-alone 24-inch pipeline from the slope to Southcentral Alaska, the so-called "bullet line." This is being pursued by another state corporation, the Alaska Gas Development Corp., or AGDC. The bullet line would be 737 miles in length and would cost about $7.5 billion.  The people working on this are getting good marks for the work they’re doing. There is criticism that the political sideboards on the project, mainly a restriction on the amount of gas that can be shipped because of the state’s contract with TransCanada, could cripple its economics.  Finally, there is a 800-mile pipeline from the slope to Valdez, parallel to the trans-Alaska oil pipeline, that could serve a possible natural gas liquefaction, or LNG, plant. This is promoted by the Alaska Gasline Port Authority, or AGPA. The port authority was formed by municipalities and is not a state corporation.